Boat steering stabilizer

ABSTRACT

A steering stablizer for a boat towing in a load is disclosed herein in which the stabilizer includes an auxiliary rudder rotatably mounted on the transom by a torque device offset from the longitudinal center line of the boat. A control linkage is carried on the torque device and is coupled to the load via a tow line. The control linkage is responsive to transverse movement of the load to rotate the torque device and the auxiliary rudder in the direction of the load movement so that the heading of the boat is unaffected by the load-induced side forces at the stern of the boat.

XR 3118389660 SR United $13165 Patent 1191 Frisbee 1 Oct. 1, 1974 541BOAT STEERING STABILIZER 3,469,552 9/1969 Patricit 114/236 [76]Inventor: Lloyd E. Frisbee, 20055 Hiawatha 3.611977 10/197 Mosvold114/236 Angeles Calif 91311 7 Primary ExaminerLloyd L. King [22] Filed:June 16, 1972 Assistant Examiner-Randolph A. Reese [2]] pp No 263 403Attorney, Agent, or FirmRoger A. Marrs 1 1 1 [57 ABSTRACT [521' Cl114/235 114/162 ii ,2 A steering stablizer for a boat towing in el oadis dis- (5l 1 int. Cl B63b 2l'/5 6 wihfimmchihe'smmizemnaudes gaming 521Field of Search..,.. 9/310 R, 310 A; 114/144 R,wdderfimblwoumeion1-ther-"ansombee 4/162 163 164 235 R 235 ws 236 t0rgi1e giev1c e offset from the longitudinal center line 1 15/6 l of theboat. A control linkage is carried on the torque device and is coupledto the load via a tow line. The [56] References Cited control linkage isresponsive to transverse movement of the load to rotate the torquedevice and the auxili- UNITED STATES PATENTS 1 ary rudder in thedirection of the load movement so 453,338 6/189l Frostad il4/l62 thatthe heading of the boat is unaffected the load- Z g 3 induced sideforces at the stern of the boat. 0s 3,221,699 12/1965 Vidach 114/162 13Claims, 7 Drawing Figures BOAT STEERING STABILIZER BACKGROUND OF THEINVENTION l. Field of the Invention The stabilizing means includes arotatable auxiliary rudder carried on the transom of the towing vesseloffset from the longitudinal center line of the vessel by means of aturning or torque-sensitive device. Control This invention relates toautomatic stabilizing means 5 linkage is operably coupled between a towline confor a boat and, more particularly, to an automatic,

means responsive t q latera l moygrpgjyiaiowed [63rd,

to maintain the heading and course of the boat.

2. Description of the Prior Art In the boating field, it is well knownthat the steering of a boat is accomplished by moving the boats stem toeither the right or left of its longitudinal center line. Means forproviding this movement may take the form of the discharge force of anengine via the propeller or 'by means of a controllable rudder or acombination of both. However, when the boat is towing a load, side loadforces are induced to the stern of the towing boat due to lateral shiftsor displacement of the towed load. These side forces cause the boat toturn or pivot approximately one-third aft of its bow so that theintended heading or course of the boat is altered significantly Thisaltered heading must then be corrected by the operator of the boatthrough his conventional steering means so that the boat is directedback onto the intended heading.

Obviously, not only is the steering of the boat greatly restricted butthe overall maneuverability of the boat is adversely affected andsubstantial skill of the boat operator is required to steer andcompensate for the shifting lateral side load forces. This problem isparticularly acute when the boat is employed for towing one or morewaterskiers, since the skier is constantly moving across the stern ofthe boat in a substantial are from the point of two rope connection atthe transom of the boat. For example, as a waterskier moves laterally toeither side, he produces a side load and turning moment on the boat thattends to pull the stern of the boat towards the side where the skier islocated and, as the stern moves in this direction, the boat is turned inthe opposite direction. To keep on course, the operator is required tomaintain a constant vigil and must continually correct for the side pulland turning tendency by means of the steering wheel being controllablyconnected to the boat motor.

In the past, attempts have been made to overcome the adverse steeringeffects of a towed load and such attempts are disclosed in US. lettersPat. Nos. 394,174; 398,631 and 1,968,577. However, these prior devicesrelate to remote controlled means for steering a towed boat rather thanfor enhancing the control of the steering of the towing boat. Theseprior devices are also extremely complex and are directed more towardssituations in which a towed boat is following almost in a direct linewith the towing boat as opposed to a widely swinging load such as awaterskier.

Therefore, a long standing need has existed to provide an automaticmeans for overcoming the adverse effects of said load force generationinduced at the stern of a towing boat due to an extremely wide lateraldisplacement of a towed load.

SUMMARY OF THE INVENTION Accordingly, the problems and difficultiesencoun tered with. lateral swinging loads towed from a vessel or 65nected to the towed load and the turning device so as to be responsiveto lateral shifts of the towed load for rotating the rudder in thedirection of the induced side force load at the stern of the towingvessel.

10 Therefore, it is among the primary objects of the present inventionto provide a novel automatic stabilized steering control for a towingvessel responsive to induced side forces at its tg rp togounteract theresul 0 lateral loads induced by a laterally moving towed load.

Another object of the present invention is to provide an auxiliaryrudder mechanism offset from the standard steering device of the boatoperable in response to swinging side load forces generated by alaterally moving towed load to maintain the course and heading of theboat.

Another object of the present invention is to provide a novel automaticstabilizing means for preventing a 30 waterskier or skiers fromcontinuing pulling the tow boat off its course as the skiers maneuverfrom side-toside behind the towing boat.

Yet another object of the present invention is to provide a novel towingstabilizer carried on the stern of the 5 towing boat for automaticallycounteracting the side swing and turning tendency of the boa-t which awaterskier produces without the attendent need of corrective steering bythe operator of the tow boat.

BRIEF DESCRIPTION OF THE DRAWINGS The features of the present inventionwhich are believed to be novel are set forth with particularity in theappended claims. The present invention, both as to its organization andmanner of operation, together with 5 further objects and advantagesthereof, may best be un- 50 water ski tow boat towing a waterskiertherebehind',

FIG. 2 is a diagrammatic view similar to the view shown in FIG. 1 of atow boat incorporating the present invention for towing a skier throughthe water;

FIG. 3 is an enlarged perspective view ofone form of an automaticstabilizing means of the present invention as employed on the tow boatshown in FIG. 2;

FIG. 4 is a top plan view of the automatic stabilizing means shown inFIG. 3;

FIG. 5 is a side elevational view, partly in section, of an adjustablelink employed in the stabilization means shown in FIG. 4 as taken in thedirection of arrows 55 thereof;-

FIG. 6 is a perspective view of another embodiment of an automaticstabilizing means incorporating the present invention; and

FIG. 7 is a top plan view of still another version of the automaticstabilizing means of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, aconventional water ski tow boat is indicated by numeral and isillustrated as heading on a course in the direction of arrow 11. Boat 10is powered and steered by a conventional motor 12 I via-a steering wheelunder the control of the operator of the boat 13. As is the usualpractice, motor 12 is located on a transom 14 constituting the stern ofthe boat and is substantially located along the longitudinal center lineof the boat. Boat 10 is employed as a tow boat for towing a waterskier15 therebehind. The skier grasps a handle 16 which is connected to oneend of a tow rope 17 while the opposite end of the tow rope is securedto transom 14 by a fixed fastener attachment means 18. Attachment means18 is of a stationary de- 7 sign and generally takes the form of anapertured fitting or the like. As the waterskier 15 is towed behind theboat 10, the skier maneuvers laterally along a wide are behind the boat.During such maneuvering, the skier produces a side pull or load at thestern of the boat in the direction of arrow 20 which induces a turningmoment on the boat tending to pull the stern of the boat towards theside where the skier is located. Also, this induced side force tends toturn the bow of the boat in the opposite direction from the arrow 20whereby the heading of the boat turns in the direction of arrow 21. Theturning moment of the boat in the direction of arrow 21 changes theheading and course of the boat from its intended course 11. To keep theboat on course, the operator must continuously correct for the side pullin the direction 20 and the turning tendency in the direction of-arrow21 by means of the steering wheel and the normal steering control suchas the motor 12. If more than one waterskier is being towed, the problemis compounded and at times, corrective steering by the operator isextremely difficult, if not impossible.

In contract to the above-described conventional situation, FIG. 2illustrates the same boat 10 incorporating the automatic stabilizingmeans of the present invention. The automatic stabilizing means isindicated in the general direction of arrow 22 where it is mounted on J]is attached to the agtgn atic stabilizing means and trated as mounted onthe stern of the boat; however; it is to be understood that anyconventional motor or rudder combination may be employed for normalsteering of the boat. The automatic stabilizing means 22 comprises anauxiliary rudder 26 submerged in the water preferably below thewaterline of the boat. The auxiliary rudder is carried on the end of anauxiliary rudder' turning or torque rod 27 that is rotatably carried onthe "tends to'swing the s erfi'afsaitm1535mm; opposite" thskiei' as'indicated by that 23 and to turn the boat back on its intended course 11as indicated by the arrow 24. In this manner, the stabilizing means ofthe present invention automatically counteracts the side swing andturning tendency which the skier 15 produces without the need ofcorrective steering by the operator of the boat. Side force 20 inducedby the lateral load of the skier is compensated for by the side force 23in response to the automatic stabilizing means. The turning moment 21 ofthe boat induced by the lateral load of the skier is counteracted by theautomatic stabilizing means when it induces the opposite turning moment24.

Referring now in detail to FlG. 3, the stabilizing means of the presentinvention is illustrated in the gen eral direction of arrow 22 and isoperably carried on transom 14 of boat 10 substantially offset from thelongitudinal center line of the boat as is indicated by numeral 25. Forpurposes of clarity, motor 12 is not illusports 28 and 30. The end ofrod 27 from its carrying rudder 26, is provided with a control crank 31which projects outwardly from the transom 14 substantially in. verticalalignment with the rudder 26. A ski rope attachment arm 32 is arrangedin parallel relationship with the control crank 31 by means of aninterconnecting link 33. The opposite ends of link 33 are pivotallyattached to the arm 32 and control crank 31, respectively, by pins orthe like. Attachment arm 32 includes a rod 34 rotatably carried on abearing support 35 fixedly secured to the transom in fixed spacedrelationship with respect to the rod bearing support 30. The oppositeend of arm 32 from its end connected to the rod 34 is formed with anattachment means 36, such as a closed eye, for detachably securing theend of tow rope 17 therewith.

It is to be noted that a significant relationship is established byhaving the attachment arm 32 equal in length to the distance from thepivot axis to the center of pressure of the auxiliary rudder 26. Morespecifically, dimension A in connection with attachment arm 32 should beequal to the dimension indicated by dimension 8 associated withauxiiiary rudder 26. it" the tow rope attachment point 36 is the samedistance from the rudder pivot axis as the rudder center of pressureindicated by character B, the side force and rudder force will exactlyequal each other.

ln FIGS. 3 and 6, a diagram of the forces and important dimensions ofthe ski-boat stabilizer are shown:

ln the diagram, the following symbols and notation are used:

F(side-force) Skiers Side-Force component F(rudder) Rudder Force T(rope)Tow-rope Tension or Pull-Force c.p.(rud.) rudder center-of-pressure Adistance from rope attach point to pivot-point (rudder shaft axis) (or,length of tow-rope attach arm) B distance from rudder center-of-pressureto rudder shaft axis, or pivot point it can be seen that for anycondition the Side Force moment on the crank and the Rudder moment willbe equal and opposite as stated by the following relationship:

l. F(side-force) X A F(rudder) X B From this relationship, it is alsoclear that if dimension A is set equal to dimension B, the rudder force,F (rudder) will equal the skiers side-force component, F(sideforce).

This is the situation pictured in FIGS. 3 and 6. In this situation theskiers side-force, or side pull, on the stern of the boat is exactlycounterbalanced by the force being produced by the rudder in theopposite direction, and the boat does not turn.

it", however, dimension A does not equal dimension B, it is clear fromrelationship (1), above, that the rudder-force F(rudder) will be eithergreater or less than the skicr's side-force, F(side-force), and sincethese forces tending to move the stern of the boat one direction or theother are not balanced, the boat will turn opposite the direction of thelarger force.

For example, if A were longer than B, the skier would have leverage toturn the rudder to an angle that would produce a rudder force greaterthan the skiers sideforee (thus turning the boat towards him). If A wereshorter than B, the skiers leverage would not turn the rudder far enoughto balance his side-force (the boat would turn away from him).

From the above description, it is clear that the signifi cance ofmaintaining A and 8 equal is that the sideforce produced by the rudder,F(rudder), will balance the skiers side-force F(side-forc-e). Thus therudder stabilizes the boat against the skier but does not steer it.

Referring now to FIG. 4, it can be seen that as the attachment arm 32 isrotated in its bearing 35 responsive to lateral movement of the towedload as indicated by the are 37, control link 31 will follow via theintercon- 'necting link 33 so that the auxiliary rudder 26 will alsoattachment arm and control crank may be composed of telescoping members,such as is illustrated in FIG. 5, so that they may be varied in length,as desired. In this instance, attachment arm 32 is illustrated having atube portion 38 and a rod portion 40 that are in slidable telescopingrelationship. The tube portion and rod portion are provided withapertures that when in registry, will readily receive a detachablefastener such as a spring pin 41. However, it is essential that thesubstantial lengthof the two members be of equal length so that the link33, attachment arm, control crank and the transom of the boat forma'parallelogram in plan view when the boat is towing under load.

Referring now to FIG. 6, another embodiment of the present invention isillustrated which represents a simplified version of the boat towingstabilizer wherein the tow rope I? is attached directly to the controlcrank 31 by provision of attachment means 36' carried thereon. It isunderstood that the torque device 27, auxiliary rudder 26 and thebearing supports 28 and 30 are identical to the construction shown inFIG. 3. As described previously, the distance A which is the length ofthe control crank is equal to the distance B of the rudder so that theside force and rudder force will be exactly equal with respect to eachother.

Other embodiments and versions of the invention are contemplated such asis shown in FIG. 7 wherein an endless cable 46 is trained around theperiphery of a pulley 45 and a pulley 47. Both pulleys are rotatablymounted on the transom M by suitable bearing supports 48 and 50,respectively. It is to be noted that'the ski rope 17 is detachablyconnected to the outside side of the cable loop by an attachmentconnector 51. Also, torque device 27 may be rotated by coupling thecontrol crank 31 to the outside side of the cable loop by any suitablemeans. Therefore, as the ski rope moves from side to side, cable 46 willmove accordingly and effect rotation of the torque device 27 and thedownwardly depending auxiliary rudder attached thereto.

In view of the foregoing, it can be seen that the automatic towingstabilizer of the present invention provides a means for counteractingthe side swing and tuming tendencies encountered by a towing boat whentached by means of a pivot pin. The outboard end of the link 33 isattached by means of a pivot pin to the attachment arm 32 and thetow'rope is attached to the attachment arm 32 by any suitable means. Itis to be understood by duplicating this arrangement at the other side ofthe transom 14, attachment of two tow ropes may be permitted.

By employment of the automatic towing stabilizer means of the presentinvention on a tow boat and when the tow rope is attached to the controlcrank as shown in either FIGS. 3 or 6, the control crank will swing inthe direction that the rope is pulling and thus turning the rudder inthe same direction, but not necessarily the same angle. The forcedeveloped by the rudder in this position tends to swing the stem to theside opposite the skier and to turn the boat back towards the skier. Inthis manner, the towing stabilizer automatically counteracts the sideswing and turning tendency which the skier produces without need ofcorrective steering by the operator of the boat.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art thatchanges and modifications may be made without departing fromthisinvention in its broader aspects and, therefore, the aim-in theappended claims is to cover all such changes and modifications as fallwithin thetrue spirit and scope of this invention.

What is claimed is:

l. A steering stabilizing rnean s n ajoat, having a primary steer ngappa a t us for, towingmlly swinging load from a tow line having itsopposite ends connected to the load and boat respectively comprising:

an auxiliary steering means in addition to and in lll y t nsmean incudesarurlderso f ettrcm.

leading edge of said rudder to the center of rudder pressure. t

4. The invention as defined in claim 3 including an attachment armrotatably carried on the transom of the boat in spaced apart parallelrelationship with respect to said crank arm;

an interconnecting link pivotally secured at its opposite ends to saidattachment arm and said crank arm respectively; and

said attachment means carried on the free endof said attachment arm.

5. The invention as defined in claim 4 including means for adjusting thelength of said attachment arm and said crank arm.

6. The invention as defined in claim 3 wherein said torque devicecomprises a turning shaft mounted in bearing supports attached to thetransom of the boat. 7

7. The invention as defined in claim 1 wherein said control meansincludes an endless cable carried about a pair of spaced apart pulleysrotatablymounted on the transom of the boat wherein said attachmentmeans is carried on one side of said cable and said auxiliary steeringmeans is carried on the opposite side of said cable 8. A steeringstabilizer for a boat, having a primary steering apparatus, towing atleast one waterskier by a tow line connected at its opposite ends to theskier and the boat respectively comprising the combination of:

rudder means movably carried at the stern of the boat below the waterline in spaced relationship to said primary steering apparatus thereof;and control linkage means carried on said boat operably coupled to saidrudder means and connected to said tow line responsive to lateralmovement of the skier for translation into a side force at the stern ofthe boat via said rudder means to counteract an opposite side force atthe stern-of said boat induced by the load of the water skier wherebysaid boat automatically maintains its intended heading and course viasaid primary steering apparatus.

9. The invention as defined in claim 8 wherein said rudder meansincludes a blade downwardly depending from a torque rod rotatablycarried about a vertical axis; and

said control linkage means includes a control arm connected to saidtorque rod in fixed spaced relationship to said blade and lying in thesame vertical plane as said blade.

10. The invention as defined in claim 9 wherein the dimensional lengthof said control arm is equal to the dimensional distance from theleading edge of said blade to its center of pressure.

11. The invention as defined in claim 8 including a pivot connectionattaching the end of said tow rope to said control linkage means; andwherein the dimensional distance from the pivot point of said pivotconnection to line attachment point is sub stantially the same as thedimensional distance from the rudder pivot axis to the center ofpressure of said rudder means.

12. The invention as defined in claim8 including a pivot connectionattaching the end of said tow rope to said control linkage means wherebya balancing force is generated at the stern of the boat equal to theload of the skier by the submerged rudder means.

13. The invention as defined in claim 12 wherein said rudder means isoffset from the longitudinal center line of the boat.

1. A steering stabilizing means on a boat, having a primary steeringapparatus for, towing a laterally swinging load from a tow line havingits opposite ends connected to the load and boat respectivelycomprising: an auxiliary steering means in addition to and in spacedrelationship to the primary steering apparatus rotatably carried on thestern of the boat below the waterline thereof; control means operablycarried on said auxiliary steering means for rotating said auxiliarysteering means in response to movement of said control means; andattachment means carried on said control means detachably connected tothe tow line and said control means being responsive to move laterallyfollowing the swing of the load so that said auxiliary steering meanscounteracts any tendency of the boat to deviate from its intended courseand heading.
 2. The invention as defined in claim 1 wherein saidauxiliary steering means includes a rudder offset from the longitudinalcenterline of the boat and from the primary steering apparatus; and saidcontrol means includes a torque device rotatably mounted on the transomof the boat and a crank arm lying in a vertical plane with said rudder.3. The invention as defined in claim 2 wherein the dimensional length ofsaid crank arm is substantially equal to the dimensional distance fromthe leading edge of said rudder to the center of rudder pressure.
 4. Theinvention as defined in claim 3 including an attachment arm rotatablycarried on the transom of the boat in spaced apart parallel relationshipwith respect to said crank arm; an interconnecting link pivotallysecured at its opposite ends to said attachment arm and said crank armrespectively; and said attachment means carried on the free end of saidattachment arm.
 5. The invention as defined in claim 4 including meansfor adjusting the length of said attachment arm and said crank arm. 6.The invention as defined in claim 3 wherein said torque device comprisesa turning shaft mounted in bearing supports attached to the transom ofthe boat.
 7. The invention as defined in claim 1 wherein said controlmeans includes an endless cable carried about a pair of spaced apartpulleys rotatably mounted on the transom of the boat wherein saidattachment means is carried on one side of said cable and said auxiliarysteering means is carried on the opposite side of said cable.
 8. Asteering stabilizer for a boat, having a primary steering apparatus,towing at least one waterskier by a tow line connected at its oppositeends to the skier and the boat respectively comprising the combinationof: rudder means movably carried at the stern of the boat below thewater line in spaced relationship to said primary steering apparatusthereof; and control linkage means carried on said boat operably coupledto said rudder means and connected to said tow line responsive tolateral movement of the skier for translation into a side force at thestern of the boat via said rudder means to counteract an opposite sideforce at the stern of said boat induced by the load of the water skierwhereby said boat automatically maintains its intended heading andcourse via said primary steering apparatus.
 9. The invention as definedin claim 8 wherein said rudder means includes a blade downwardlydepending from a torque rod rotatably carried about a vertical axis; andsaid control linkage means includes a control arm connected to saidtorque rod in fixed spaced relationship to said blade and lying in thesame vertical plane as said blade.
 10. The invention as defined in claim9 wherein the dimensional length of said control arm is equal to thedimensional distance from the leading edge of said blade to its centerof pressurE.
 11. The invention as defined in claim 8 including a pivotconnection attaching the end of said tow rope to said control linkagemeans; and wherein the dimensional distance from the pivot point of saidpivot connection to line attachment point is substantially the same asthe dimensional distance from the rudder pivot axis to the center ofpressure of said rudder means.
 12. The invention as defined in claim 8including a pivot connection attaching the end of said tow rope to saidcontrol linkage means whereby a balancing force is generated at thestern of the boat equal to the load of the skier by the submerged ruddermeans.
 13. The invention as defined in claim 12 wherein said ruddermeans is offset from the longitudinal center line of the boat.